1. Field of the Invention
This invention relates generally to methods and devices for alleviating erectile impotency, and specifically to unitary, inflatable devices which may be implanted within the corpus cavernosum of the penis.
2. Brief Description of the Background Art
A number of devices are commercially available for enabling those with erectile impotency to achieve an erection. These devices are generally implanted within the corpus cavernosum of the penis. Normally two such devices are utilized, one implanted into each corpus cavernosum. Modern day technology has evolved from the early rigid rod devices that produced a permanent erection. Since the user had no ability to control the operation of the device, the rigid rod approach had serious drawbacks.
The so-called inflatable penile prostheses generally include a reservoir, a pump, and a pressure chamber. Fluid is pumped from the reservoir by the pump to the pressure chamber in order to achieve an erection. Early devices such as that disclosed in U.S. Pat. No. 3,853,122 to Strauch, et al., used an external pump and a simple tube and valve mechanism. U.S. Pat. No. 3,954,102 to Buuck discloses an improvement wherein the device may be manually operated in a convenient fashion through the use of a bypass valve means.
U.S. Pat. No. 4,009,711 discloses a penile prosthesis with an external pump and a non-distensible tail that is implanted at the root of each corpus cavernosum under the puboischiatic rami. The patent indicates that the taillike portion provides increased stability when the penis becomes erect and decreases considerably the volume of fluid needed for an adequate erection.
A penile prosthesis using an inflatable hinge is described in U.S. Pat. No. 4,267,829 to Burton and Mikulich. In this patent, a tubular section includes a chamber which undergoes only a small change in volume and therefore requires minimum fluid displacement as the prosthesis transforms from a non-erect to an erect condition. Unitary penile prostheses which include a pair of concentric chambers, one of which is pressurized, are disclosed in U.S. Pat. Nos. 4,353,360 and 4,399,811. In these patents, the inner of two concentric chambers is pressurized while the outer of the two chambers acts as the fluid reservoir prior to erection. To attain an erection, fluid is pumped from the outer reservoir through a pump to the inner reservoir. Thus, the total volume of the two chambers is always constant.